Because of a growing appreciation for the benefits of regular exercise; and because constraints of time and space prevent many persons from indulging in activities such as running, swimming and walking, the market for exercise equipment is rapidly increasing. It is generally desirable to exercise a number of different muscles over a fairly large range of motion so as to provide for even physical development and a maximum level of aerobic exercise. It is further desirable that exercise equipment provide a smooth, relatively natural motion so as to avoid jarring or irregular strains which can damage muscles and joints. It is also desirable that exercise equipment be relatively easy to use and of simple, low cost construction.
While a number of different exercise systems are known in the prior art, such systems suffer from a number of shortcomings which limit their utility. Stationary bicycles are widely used; however, they are employed in a sitting position and consequently, the number of muscles exercised is small. Furthermore, the range of motion provided by a stationary bicycle is fairly limited. Stationary devices for simulating cross country skiing are also in widespread use. While these systems exercise more muscles than do stationary bicycles, the relatively flat, shuffling foot motion provided thereby does not adequately exercise all of the leg muscles through a wide range of motion. Stair climbing equipment also exercises more muscles than do stationary bicycles; however, the rather limited up and down motion provided thereby does not exercise leg muscles through a large range of motion. Treadmills and the like permit walking or jogging in a relatively limited area; however, they can be quite jarring to knee and ankle joints, and many users find it difficult to maintain balance on a treadmill.
U.S. Pat. No. 4,720,093 shows a climbing type exerciser. U.S. Pat. No. 4,509,742 shows a stationary bicycle which provides for arm motion. U.S. Pat. No. 2,603,486 shows a bicycle type exerciser providing for combining arm and leg motions. U.S. Pat. No. 5,039,088 shows another bicycle type exerciser providing for hand motion.
Despite the large number of exercise devices known in the prior art there is still a need for an exercise device which is simple to manufacture and use and which provides for a smooth, natural action and which exercises a relatively large number of muscles through a large range of motion. The exercise device of the present invention, as will be described herein below, provides for a smooth stepping-running motion which exercises a user's legs more fully than cycling or skiing devices. The device of the present invention may also be employed to provide arm and shoulder motions. The smooth action of the device prevents trauma to joints and muscles.
These and other advantages of the present invention will be readily apparent from the drawings, discussion and description which follow.